Lookin to do the exhuast to get ready for the gm s/c, one last thing im trying to figure out is with a pacesetter header there is one that says This header includes a flanged 2-1/4 collector, which i assume means the outlet is 2.25?

here


and another that says it has a 3.0inch
here


now i wanted to run a 2.5inch because i thought it would be best with the charger for my 05 eco, but if the outlet on either header isnt 2.5inch, should i upgrade to a whole 3.0inch setup? or will using the 2.25inch not really hurt anything with 2.5inch everything else???

i appreciate any help!

If you look at the first link, notice the end is swedged down in size. If you're looking to use a lager exhaust, cut the smaller portion off and get the appropriate sized reducer to hook up to your system.